Sure, here is your (quick) summary from someone who speaks German. My comments are in brackets:
- The game plays 23 years before Drakensang during the "Khom-War", the war between the Novadi caliphate and (the totally decadent and awesome) Al'Anfa. The titular river also refers to the actual great river in the region.
- There will be two new archetypes. Dwarven spellcasters and another northern warriortype.
- The game will have full voice acting.
- The party will have a house boat on the river. So your "abode" will often be very close to the actual quest area (great idea IMO).
- The game will be less linear, and you will have more choices as to when you visit which locations.
- Characters will have more depth, be more gray. The player will get to make some decisions that have long-lasting effects on the gameworld.
- There will be significantly less NPCs to choose from. Some of them will be familiar from the first game.
- Combat will be more tactical, as it will be even more important to pay attention to the strengths and weaknesses of enemies. The player will have access to miracles from the Gods.
- The game will use the same engine as Drakensang 1. Textures will be hi-res from the start. NPC gestures will be improved due to new animations.
- Drakensang 1 used "speedtree" for the flora. In the new games, trees will be designed by hand to make the game look more "European". The developers want trees to have bigger trunks.
The last piece of information made me laugh. It's by far the most random chunk of info on this list.